High-Grade Sarcoma Arising in Association With an Intraosseous Lipoma

CASE: A 78-year-old man was followed for an incidentally found, asymptomatic lesion in his right proximal femur that was unchanged radiographically for 11 years. He developed pain and was believed to have experienced a stress fracture through the lesion. The lesion was biopsied, showing a high-grade pleomorphic sarcoma with an underlying senescent intraosseous lipoma. He was ultimately treated with wide excision and reconstruction of the proximal femur. CONCLUSION: This case highlights the importance of obtaining a tissue diagnosis for lesions that become symptomatic.